<!DOCTYPE html>
<html>
<head>
<style>
    body {
        height: 2000px;
    }

    .container {
        height: 200px;
        width: 300px;
        border: 4px solid black;
        overflow-y: scroll;
        resize: both;
    }

    .contents {
        height: 1000px;
    }

    .box {
        position: relative;
        z-index: 1;
        height: 100px;
        width: 100px;
        margin: 10px;
        background-color: blue;
    }

    .surface {
        opacity: 0.5;
    }

    #fixed {
        position: fixed;
        z-index: 0;
        background-color: green;
        left: 50px;
        top: 200px;
        height: 200px;
        width: 200px;
    }
</style>
</head>
<!--
  This test ensures that render surfaces grow to accomodate clip children.
  If this test is working, you should see that the green box is square.
-->
<body>
    <div class="surface">
        <div class="box"></div>
        <div class="container">
            <div>
                <div class="box"></div>
                <div class="container">
                    <div id="fixed"></div>
                    <div class="box"></div>
                    <div class="box"></div>
                    <div class="box"></div>
                    <div class="box"></div>
                    <div class="box"></div>
                </div>
            </div>
        </div>
    </div>
</body>
</html>
